User experience (UX) refers to the interaction of person with a system including their actions and perceptions, e.g., what the person wants to do, what they actually do and their feels about using the system, etc. User experience highlights the experiential, affective, meaningful and valuable aspects of human-computer interaction and product ownership, but it also covers a person's perceptions of the practical aspects such as utility, ease of use and efficiency of the system. User experience is subjective in nature, because it is about an individual's performance, feelings and thoughts about the system. User experience is dynamic, because it changes over time as the circumstances change.
Recent advances in mobile, ubiquitous, social, and tangible computing technologies have moved human-computer interaction (HCI) into practically all areas of human activity. This has led to a shift away from usability engineering to a much richer scope of user experience, where user's feelings, motivations, and values are given as much, if not more, attention than efficiency, effectiveness and basic subjective satisfaction.